machined: add UnregisterMachine method

This is the opposite of RegisterMachine: machined knows that the machine is
"gone", but doesn't do anything on its own. We already had TerminateMachine,
but that would stop the unit, which isn't always wanted.

src/machine/machine-dbus.c

@@ -62,6 +62,34 @@ static int property_get_netif(
         return sd_bus_message_append_array(reply, 'i', m->netif, m->n_netif * sizeof(int));
 }
 
+int bus_machine_method_unregister(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        Machine *m = userdata;
+        int r;
+
+        assert(message);
+        assert(m);
+
+        r = bus_verify_polkit_async(
+                        message,
+                        CAP_KILL,
+                        "org.freedesktop.machine1.manage-machines",
+                        NULL,
+                        false,
+                        UID_INVALID,
+                        &m->manager->polkit_registry,
+                        error);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return 1; /* Will call us back */
+
+        r = machine_finalize(m);
+        if (r < 0)
+                return r;
+
+        return sd_bus_reply_method_return(message, NULL);
+}
+
 int bus_machine_method_terminate(sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Machine *m = userdata;
         int r;

src/machine/machine-dbus.h

@@ -11,6 +11,7 @@ char *machine_bus_path(Machine *s);
 int machine_object_find(sd_bus *bus, const char *path, const char *interface, void *userdata, void **found, sd_bus_error *error);
 int machine_node_enumerator(sd_bus *bus, const char *path, void *userdata, char ***nodes, sd_bus_error *error);
 
+int bus_machine_method_unregister(sd_bus_message *message, void *userdata, sd_bus_error *error);
 int bus_machine_method_terminate(sd_bus_message *message, void *userdata, sd_bus_error *error);
 int bus_machine_method_kill(sd_bus_message *message, void *userdata, sd_bus_error *error);
 int bus_machine_method_get_addresses(sd_bus_message *message, void *userdata, sd_bus_error *error);

src/machine/machine.c

@@ -449,13 +449,16 @@ int machine_stop(Machine *m) {
 int machine_finalize(Machine *m) {
         assert(m);
 
-        if (m->started)
+        if (m->started) {
                 log_struct(LOG_INFO,
                            "MESSAGE_ID=" SD_MESSAGE_MACHINE_STOP_STR,
                            "NAME=%s", m->name,
                            "LEADER="PID_FMT, m->leader,
                            LOG_MESSAGE("Machine %s terminated.", m->name));
 
+                m->stopping = true; /* The machine is supposed to be going away. Don't try to kill it. */
+        }
+
         machine_unlink(m);
         machine_add_to_gc_queue(m);
 

src/machine/machined-dbus.c

@@ -448,6 +448,10 @@ static int redirect_method_to_machine(sd_bus_message *message, Manager *m, sd_bu
         return method(message, machine, error);
 }
 
+static int method_unregister_machine(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        return redirect_method_to_machine(message, userdata, error, bus_machine_method_unregister);
+}
+
 static int method_terminate_machine(sd_bus_message *message, void *userdata, sd_bus_error *error) {
         return redirect_method_to_machine(message, userdata, error, bus_machine_method_terminate);
 }
@@ -1137,6 +1141,7 @@ const sd_bus_vtable manager_vtable[] = {
         SD_BUS_METHOD("CreateMachineWithNetwork", "sayssusaia(sv)", "o", method_create_machine_with_network, 0),
         SD_BUS_METHOD("RegisterMachine", "sayssus", "o", method_register_machine, 0),
         SD_BUS_METHOD("RegisterMachineWithNetwork", "sayssusai", "o", method_register_machine_with_network, 0),
+        SD_BUS_METHOD("UnregisterMachine", "s", NULL, method_unregister_machine, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("TerminateMachine", "s", NULL, method_terminate_machine, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("KillMachine", "ssi", NULL, method_kill_machine, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("GetMachineAddresses", "s", "a(iay)", method_get_machine_addresses, SD_BUS_VTABLE_UNPRIVILEGED),

src/machine/org.freedesktop.machine1.conf

@@ -76,6 +76,10 @@
                        send_interface="org.freedesktop.machine1.Manager"
                        send_member="OpenMachineShell"/>
 
+                <allow send_destination="org.freedesktop.machine1"
+                       send_interface="org.freedesktop.machine1.Manager"
+                       send_member="UnregisterMachine"/>
+
                 <allow send_destination="org.freedesktop.machine1"
                        send_interface="org.freedesktop.machine1.Manager"
                        send_member="TerminateMachine"/>